Backdraft diverter



July 11, 1939. F Rs 2,365,811

BACKDRAFT DIVERTER Filed March 21, 1938.

In Her: 50? Fwy/MB ETA-Rs Patented July 11, 1939 UNITED. STATES PATENT OFFICE BACKDRAFT DIVERTER Frank B. Peters, Minneapolis, Minn. Application March 21, 1938, Serial No. 197,108

2 Claims. (Cl. 126--30'7) This invention relates to a draft hood or draft accompanying drawing in which like reference regulating device adapted .to be used with a gas characters refer to similar parts throughout the burning furnace or heater. Such draft hoods several views and in which: or regulators are now generally required in a Fig. l is a view in side elevation of a furnace,

furnace room where such a .gas burning furnace a portion of the chimney, the smoke pipe con- 5 or heater is used. The general functions of necting the same and the device of the invensuch a device are to insure the ready escape of tion connected thereto;

the products of. combustion in the event of no Fig. 2 is a view in side elevation of a draft draft, back draft or stoppage beyond the draft hood embodying the present invention, some hood, to prevent a back draft from entering parts being broken away; 10 the furnace or heater and to neutralize the ef- Fig. 3 is a vertical section taken on line 33 feet of the stack action of the chimney flue upon of Fig. 4 as indicated by the arrows; the operation of the furnace or heater. .It is Fig. 4 is a horizontal section taken on line one of said purposes to prevent an undue draft l-4 of Fig. 3 as indicated by the arrows; and or pulf of air from or through the chimney from Fig. 5 is a horizontal section taken on line 15 blowing out the pilot light in said furnace or 5-5 of Fig. 2 as indicated by the arrows. heater. Referring to the drawing in Fig. 1 a furnace Such draft hoods or regulators thus have on designated generally as In is shown which will ings into the furnace room and in the devices be equipped with suitable gas burning appapreviously used these openings have been 10- ratus. While the type of furnace indicated is 20 cated at a comparatively high point in the furoi the hot air type having the air outlet connace room. There is a passage of air through duits Illa it will be understood that any type these openings from the furnace room to the of gas burning furnace or heater may he used smoke pipe and chimney and this air is thus with the invention. Furnace I ll is shown as some of the warmer air in the furnace room. having a smoke pipe connection Illb to which is 25 This passage of air thus tends to drain the heat connected smoke pipe II. Smoke pipe II as or heated air from the furnace room. The air shown, extends upwardly and then horizontally thus withdrawn must be replaced by cold air in line with the connection I2 into the chimney and the temperature of the furnace room is thus l3 or into the flue thereof. The draft hood or l d, draft regulator constituting the present inven- 30 It is an object of this invention to provide a tion comprises a member M. Member l4 has a draft hood or draft regulator which will accentral portion Ma and while this portion might complish all of the desired purposes of such a have various shapes, in the embodiment of the device and yet which will take any air which invention illustrated it is shown as substantially passes to the chimney therethrough from a point cylindrical and as having a closed top Mb. Por- 35 closely adjacent the floor of the furnace room. tion Ma has a chamber therein and conduit por- The coldest air in the furnace room is thus tions I and Md project from either side therepassed up the chimney and the warmer air some of, the same having flaring portions Me and Mi distance above the floor is conserved so that a respectively extending to the sides of member 40 g er temperature is maintained in the furnace I4 and suitably connected thereto in any suitable 40 room. manner as by welding. It will be noted that It is a further object o the inVentiOn to p the sides and bottom parts of portions Me and vide a draft hood or draft regu at of y Mi extend generally downward. Portion Ma simple, inexpens e and easily installed formhas top wall portions Mg therein which extend It is still another object of the invention to from opposite sides respectively downwardly to- 45 provide a draft hood or draft regu ati g device ward the center of said portion where they meet which can be easily inserted in the conduit leadand then extend downwardly in a vertical plane ing from the furnace to the chimney, said decentrally of member I4 to form a baffle plate I4h. vice having lateral extensions adapted to be It will be noted that baffle I4h extends downconnected respe v ly to the furnace and chimwardly a short distance below the connecting 60 ney and adapted to have a conduit extending portions Me and Idf. A conduit I5 is connected therefrom to the floor of the furnace room. to the bottom of member 14 and extends to or These and other objects and advantages of substantially to th floor of the furnace room in the invention will be fully set forth in the folwhich the furnace or heater II] is disposed. The

lowing description made in connection with the conduit 15 has formed therein and extending 55 thereinto closely adjacent said floor a plurality of openings l5a. When the device is installed as shown in Fig. 1, portion [4c is connected to the furnace by smoke pipe II and portion Md is connected to the chimney by smoke pipe II.

In operation, the products of combustion from the gas burner in furnace or heater ID will pass out through the portion lllb and through the smoke pipe H which is connected to portion Mc as shown in Fig. 1, These products of combustion must then pass downwardly around the lower end of baffle plate l4h which extends across portion Ida as shown in Fig. 4. Said products then pass upwardly and through portion [4d to smoke pipe II and to the chimney. This path of travel is indicated by the arrows in Fig. 3. Should there be an excessive or sudden draft through the chimney, air will be drawn in the conduit I?) through the openings lfia therein. The baffle Hlh prevents a direct draft or pull through portion H40 and the furnace, and the gas burner and, especially the pilot thereof is shielded from any such sudden draft through the chimney. Th s is particularly important when the pilot is burning and the main burner is not burning. It ire-- quently happens that there is a sudden back draft through the chimney and should this occur the air would pass back through portion Md and. would be intercepted by the bafile Mn and be re lieved through the openings I511. The bafiie l ih in this case would shield the gas burner and pilot and prevent any puff back into the furnace or heater, Should any stoppage occur in the smoke pipe beyond member I4 the products of term bustion could still escape through conduit 15 and the openings lBa so that an excessive pressure could not be created in the furnace or heater.

The member M can be made either from light cast iron or from sheet metal, Most regulations require that the thickness be at least equal to No. 26 U. S. standard gage sheet steel. The parts must be so connected that they will withstand a temperature of 1000 degrees F. without melting, softening or distortion of any part. It is desirable that the area of the conduit [5 be substantially equal to the combined areas of conduit portions Me and Md.

From the above description it will be seen that I have provided a simple and very efficient construction of a draft hood or draft regulator for a gas burning furnace or heater. The device could be cheaply made and it is quite easily installed in the standard smoke pipe, In the use of said device the air which passes from the furnace room out through the chimney and through the device is taken from a point very close to the floor of the furnace room. This air will be the coldest air in the furnace room. The warmer air at higher levels will thus be retained and conserved and the temperature of the furnace room can be maintained at a much higher point than if the warm air were taken therefrom. The inlet and outlet portions I40 and Md are of the same size as the smoke pipe ll used on the furnace or heater. The flaring portions Me and Hf insure a full capacity for the gases and an easy flow through the hood or diverter. It will thus be seen that any back draft will be diverted into conduit l5 and dissipated through openings 15a. As stated, any unusual draft through the chimney will also be relieved by drawing air through openings lBa so that all danger of extinguishing the pilot light is eliminated. The device has been amply demonstrated in actual practice and found to be very successful and efficient.

It will, of course, be understood that various changes may be made in the form, details, ar

rangement and proportions of the parts, without conduit portions extending laterally from said central portion a short distance below said top and having downwardly extending sides and bottoms connected to said central portion, said conduit portions being adapted for connection respectively to said furnace or heater and to a chimney, a vertically extending baflle plate extending across said central portion between said laterally extending portions and for some distance below the latter, a conduit connected to the bottom of said central portion and extending to the floor of said furnace room, said last mentioned conduit having openings therein adjacent said floor through which cold air may enter and pass to said chimney.

2. The structure set forth in claim 1, said central portion having walls sloping from each side of its top downwardly to said baflle plate.

FRANK B. PETERS. 

